A file encryption system based on shadow files

Abstract

The invention relates to a file encryption system based on a shadow file. The system comprises: a file encryption filter driver. When a file is opened or created by a trusted process, if the file to open or create is an encryption file or a file located in a security file directory or a security file disk, the file encryption filter driver redirects a file opening or creating operation to a temporary file directory. Then the file encryption filter driver converts an I / O operation of the trusted process to the shadow file into an I / O operation to an original file of the shadow file, and during the operation, decrypts read encryption data and encrypts plain data to be written, and keeps file information and cache data of the shadow file in file control blocks to be consistent with the file information and cache data of the original file in file control blocks. However, an untrusted process directly performs the I / O operation on the encryption file. Because the trusted process and the untrusted process have respective data caches, the problem of frequent purging a cache is avoided.

Description

technical field [0001] The invention belongs to the technical field of information security, in particular to a file encryption system based on shadow files. Background technique [0002] The file encryption system based on the bridge file system based on the file filter driver (File Filter Driver) can automatically realize the encryption and decryption of files without affecting the user's usage habits, which is an important technical means to ensure data security. However, the current transparent file encryption technology based on the file filter driver generally has the following problems. [0003] The current file system (such as the Windows file system) is a file system with a cache, that is, when an application reads the data of a file, the file system first checks whether the content to be read by the application is cached in the memory. , then directly return the data cached in the memory, otherwise, the file system reads a certain amount of file data (usually seve...

AI Technical Summary

Problems solved by technology

The problems of such a multi-FCB encrypted file system are: 1) When multiple processes access a file at the same time, the memory utilization rate and file access efficiency are low; 2) The way the operating system manages file data and file operations is changed, for example, The operating system thinks that the same file should have only one FCB and cache, and the change of this file data management method may encounter unexpected problems; 3) There is a big difference from the development of the usual file system driver

Images